FR2652580A1 - TIN COMPOUNDS (IV), WHICH CAN BE USED, ESPECIALLY AS LATENT CATALYSTS. - Google Patents

Abstract

Tin(IV) compounds optionally chelated, tetracoordinated or pentacoordinated, of general formula: <??>These compounds can be employed as latent catalysts for the preparation of polyurethane and for the crosslinking of organopolysiloxane composition after thermal decomposition within the reaction mixtures to be catalysed.

Description

The present invention relates to tin (IV) compounds

  tetracoordinated or pentacoordinated used in particular as latent catalysts. Several tin compounds have already been proposed as catalysts, in particular for: polyurethane synthesis: for example, tin chelates (US-A-3 055 845) and reaction products between tin carboxylate (IV) with a sulfonylisocyanate (DE-A-3,326,566 and

EP-A-232 541),

  the crosslinking of silicone polymers by polycondensation reaction: for example dialkyltin dicarboxylates (NOLL "Chemistry and Technology of Silicones", page 337, Academic Press, 1968 2nd edition), and dialkyltin bischelates;

(EP-A-147,323 and US-A-4,517,337).

  Tetracoordinated tin (IV) compounds which can be used as latent catalysts have been the subject of French patent applications 88/05 554 and 88/05 555, filed on April 21, 1988 in the name of the Applicant. The purpose of the present invention is to propose a new class of tetracoordinated or pentacoordinated tin (IV) compounds which are on the one hand inactive at ambient temperature (approximately 20 ° C.), in particular for the two applications mentioned above and which turn into cash

  active by raising the temperature.

  This type of compound is usually called a latent catalyst.

  The latent catalysts according to the invention correspond to the general formula:

R Y

\ /

  in which: the radicals R, which may be identical or different, are chosen from a linear or branched C1-C20 alkyl radical, a mononuclear aryl, arylalkyl and alkylaryl radical, the alkyl part of which is C1-C6,1 2 - the radicals R and R, which are identical or different, are chosen from a hydrogen atom, a cyano radical and a C1-alkyl radical; -C6s an alkoxycarbonyl radical whose alkyl part is C1-C6, and R and R may together form a saturated hydrocarbon ring having 5 to 8 carbon atoms, - the radical R is chosen from a hydrogen atom, a radical linear or branched C 8 -C 20 alkyl, a linear or branched C -C 20 alkoxy radical, a mononuclear aryl radical and a mononuclear aryloxy radical,

- a is 0 or 1.

  the radical Y is chosen from a hydrogen atom, a halogen atom, a linear or branched alkoxy radical of Ce-C20, a linear or branched acyloxy radical of C -C 20 and a chelate group of formula:

O, O-R4

(2)

  In which: the radicals R and R, which are identical or different, are chosen from an R radical and a C 1 -C 5 alkoxy radical; the radical R is chosen from a hydrogen atom, an OS R radical or R forms with R a divalent cyclic hydrocarbon radical

C5-C12

  Preferably: R is chosen from butyl, octyl and 2-ethylhexyl radicals and the two radicals R are identical, R is H, R2 is H, a = 1, R is chosen from methyl radicals, ethyl, undecyl,

  Y is H, C1, acetyloxy, lauroyloxy and acetylacetonate.

  The preferred products corresponding to formula (1) are the following: 2-acetyloxyethyl dibutyltin chloride: R 2 = butyl, R = R = H, R = methyl, Y = Cl, a = 1, - chloride 2-Lauroyloxyethyl dibutyltin: R = butyl, R = R = H, R = undecyl, Y = Cl, a = 1, 2-ethoxy-ethyl-dibutyltin chloride: R 2 = butyl, R = R = H, R = ethyl, Y = Cl, a = O, 2-acetyloxy ethyl dibutyltin acetate: R = butyl, R = R = H, R = methyl, Y = acetoxy, a = 1, lauroyloxy laurate -2 ethyl dibutyltin:

1 2 3

  R = butyl, R = R = H, R = undecyl, Y = lauroyloxyl, a = 1, acetyloxy-2-ethyl-dibutyltin acetylacetonate: R 2 = butyl, R = R = H, R = methyl, Y = acetylacetonate (2-penten-2-oxy-2), a = 1, 2-lauroyloxyethyl-dibutyltin acetylacetonate: R 2 = butyl, R = R = H, R = undecyl, Y = acetyl acetonate

(2-penten-2-one oxy-2), a = 1.

  2-acetyloxyethyl-dibutyltin hydride: R 2 = R 3 = R 2 = m-methyl a = 1 R = butyl, R = R = Y = E, R = methylet a = 1 - 4 - - lauroyloxy-2 hydride ethyl dibutyltin: R = buyle, R1 = R2 = y = H, R3 = undecyl and a = 1, The compounds of formula (1) where Y is H, can be prepared by addition reaction preferably of a large excess molar diorgano-tin dihydride of formula (3): R Sn H (3) in which the radicals R. identical or different, have the same meaning as formula (1) above on a similar derivative of formula (4):

  Wherein R, R, R and a have the same meaning as

formula (1) above.

  The hydrides of formula (I) are thus obtained in which Y is in general in a mixture with at least 20% by weight of the tin compound of formula R 2 R (CHR) (R) R, R, R , R and

  a have the same meaning as formula (1).

  The dihydrides of formula (3) are, for the most part, known and described in the literature. In the case where they are new products, they can be obtained by reduction of diorganotin dichloride

  corresponding by lithium aluminum hydride.

- 5 -

  Another method consists in reducing the corresponding diorganotin oxide with a polydiorganosiloxane carrying an SiH function, for example a polyhydrogenomethylsiloxane blocked at each end by a

trimethylsilyl group.

  The carboxylates and alkoxides of formula (4) are, for the

  most known and described in the literature.

  For example, the vinyl carboxylates of formula: ## STR3 ## are obtained by transesterification of vinyl acetate on acid R COOH in an acidic medium.

R2 O

  The enol carboxylates of formula: H 2 C = C-O-C-R [formula (4): R = H. R = CH 3} are obtained by reaction of the ketone H 3 C

2 '3 31

  - COR on isopropenyl acetate in acid medium.

  The hydrostannation reaction of a product of formula (3) on a product of formula (4) is preferably carried out by reacting at least three moles of product of formula (3) with two moles of product of formula (4) at room temperature in a hydrocarbon organic solvent such as anhydrous cyclohexane. The reaction mixture is

  subjected to U.V. radiation (360 nm).

  The hydrostannation reaction may also be carried out without a solvent in the presence of a free radical generator such as, for example,

  presence of AIBN (azobisisobutyronitrile) at a temperature of 70-80 C.

  The tin halides of formula (1) where Y is a halogen atom, preferably chlorine, may be prepared according to one of the two following methods: the first method consists in carrying out the halogenation of the hydride corresponding formula (1) o Y = H by a halogenating agent which in the case of chlorination, is advantageously carbon tetrachloride, depending on the reaction: - 6 -

O O

  R2SnH {CHR CHR 0 (C); 3} CCl4. R2SnCl (CHR CHR O (C) R) - the second method consists in carrying out the addition reaction of the diorganotin halohydride of formula: R 1. Sn H Y (5)

R /

  Y represents a halogen atom and R has the same meaning as at

  formula (1), on the enol derivative of formula (4).

  The halide of formula (1) is thus quantitatively obtained. The reaction may be carried out at room temperature in solution in an organic solvent such as anhydrous cyclohexane, under a radiation

U.V. (360 nm).

  The halohydride of formula (5) is obtained quantitatively by reaction of an equimolar mixture of dihydride of formula (3) with a

  corresponding diorganotin dihalide.

  The tin compounds of formula (1) where Y is chosen from an alkoxy, acyloxy and chelate radical may be obtained by exchange of the halogen atom of the tin halide of formula (1) corresponding to the group alkoxytacyloxy or chelate of an organometallic salt of formula: ## STR2 ## Y is an alkoxy, acyloxy or chelate radical corresponding to the definition given above to formula (1) and M is a monovalent metal such as Na,

+ - + +.

  K, Li, Ag or a quaternary ammonium.

  The reaction which is generally quantitative is preferably carried out in a hydrocarbon organic solvent such as toluene with

ambient temperature.

  The tin compounds of formula (1), which are generally liquids at room temperature, can be identified by the analytical techniques of I.R. (infra-red) and R.M.N spectroscopy. (nuclear magnetic resonance 119Sn, 13C and H) as well as by mass spectroscopy

  os05 and by measuring the MOSSBAUER effect.

  It turns out, however, that in the current state of knowledge of analytical techniques, the analytical method R.M.N. 119Sn, as described, in particular in the article by Peter J. SMITH "CHEMICAL SHIFTS OF 119Sn NUCLEI IN ORGANOTIN COMPOUNDS", page 291 et seq., Published in ANNUAL REPORTS ON NMR SPECTROSCOPY, Volume 8, 1978 ACADEMIC PRIESS, is a a method which alone is sufficiently precise to characterize the different tin compounds present in a mixture, in particular of a reaction mixture, and to make it possible to find the

  chemical formulas of most of these compounds.

  The fundamental parameter evaluated by R.M.N. 119Sn is the value of the chemical shift expressed partly in millions relative to a

  reference (usually tetramethyltin).

  The value of the chemical shift 8 is particularly sensitive to the electronegativity of the groups carried by the tin and to the variation of the coordination number of the tin atom. Specific work to characterize organotin derivatives from R.M.N. They are notably described by A.G. DAVIES and P.J. SMITH, COMPREHENSIVE

  ORGANO-METALLIC CHEMISTRY, TIN, pp. 523-519 and J. OTERA J. OF.

  Organomet. CHEM. 221, pp. 57-61 (1981).

  The compounds of formula (1) are stable at room temperature and are inactive at room temperature (25 ° C.) as polyurethane preparation catalysts and as hardening catalysts.

organopolysiloxane compositions.

  On the other hand, the compounds of formula (1) can be used as catalysts for the preparation of polyurethanes and as catalysts for curing organopolysiloxane compositions after decomposition.

  thermal within the reaction mixtures to be catalyzed.

  Indeed, the products of formula (1) subjected to an increase in temperature thermally decompose into catalytically active compounds, namely: R2SnY (CHR CHR (C) a) R2Sn-Y + R1HC = CHR

O 0 (C) RR

(6)

  The thermal decomposition of the compounds of formula (1) occurs at a temperature specific to each of the products. This temperature is

  generally between 40 and 250 C.

  The compounds of formula (6) thus released are active catalysts for the preparation of polyurethanes and / or hardening of

polyorganosiloxane compositions.

  The advantage of the latent catalysts of formula (I) is therefore to be able to mix the starting materials with the latent catalyst without catalyzing the reaction and to trigger the catalysis of the reaction by heating the mixture to decomposition of the

latent catalyst.

  This decomposition temperature, generally between 250 ° C. and 250 ° C., may be lowered by addition of an effective amount of a nucleophilic agent chosen, for example, from water, a secondary organic amine, an organic alcohol or an organosilicon compound with a function silanol and an organic mercapto functional compound (SH). By effective amount is meant from 0.001 mole to 10 moles or more of nucleophile per mole of

compound of formula (1).

  The present invention therefore also relates to a process for the preparation of polyurethane according to which an organic polyisocyanate, an organic compound containing at least two active hydrogen groups and a catalytically effective amount of a latent catalyst of formula (1) are mixed at ambient temperature and we bring the mixture at least to the

  thermal decomposition temperature of the latent catalyst.

  The latent catalyst is preferably used at a content of 0.001 to 6 parts, preferably 0.01 to 1 part by weight, calculated as weight of tin metal per 100 parts by weight of the dry extracts of

starting reagents.

- 5 -

  Polyisocyanates and organic compounds containing at least two active hydrogen groups are well known to those skilled in the art. They are for example described in US-A-3,055,845 and EP-A-232,541 cited as reference. The pot life of the reaction mixture is the same whether or not there is within said mixture a latent catalyst of formula (1). This "pot life" is at least three times longer than that observed on a reaction mixture comprising an equimolar amount of the active catalyst corresponding to that obtained.

  by decomposition of the latent catalyst of formula (1).

  The catalysis is triggered as soon as the reaction mixture is brought to a temperature at least equal to the decomposition temperature of the latent catalyst. The observed reactivity is then similar to that obtained by the use of an equimolar quantity of

corresponding active catalyst.

  The present invention therefore also relates to a process for crosslinking a polyorganosiloxane composition according to which a silanol-terminated polydiorganosiloxane (A), a polyorganohydrogen siloxane (B) and a catalytically effective amount of a latent catalyst (C) of formula (1) and the mixture is brought to a temperature equal to or higher than the thermal decomposition temperature of the latent catalyst with possible evaporation of the solvent or water,

present in the mixture.

  More specifically, the polyorganosiloxane composition comprises: A parts by weight of a polydiorganosiloxane with silanol ends, B-0.1 to 25 parts by weight of a polyorganohydrogensiloxane having at least 3 SiH groups per molecule, C - a catalytically effective amount of a latent catalyst of formula (1),

  the SiH molar ratio being between 0.6 and 10.

  SiOH The organic radicals of polymers A and B are preferably chosen from C 1 -C 6 alkyl and phenyl radicals, at least 80% by weight.

  number being methyl radicals.

- 10 -

  The decomposition temperature of the catalyst is generally between 30 and 200 C. It depends on the particular latent catalyst

  used and the presentation of the polyorganosiloxane composition.

  This decomposition temperature can be lowered by adding an effective amount of a nucleophilic agent selected from, for example, water, a secondary organic amine, an organic alcohol, a silanol functional organosilicon compound and a functional organic compound. mercapto (SH). An effective amount of nucleophilic agent is understood to mean from 0.001 to 10 moles and more nucleophile per mole of

Tin of formula (1).

  Thus, for the polyorganosiloxane compositions without solvent and in solution in an organic solvent, this decomposition temperature is close to the specific intrinsic decomposition temperature of the latent catalyst. For these two types of compositions it is often possible to package the compositions in a single package with a

  storage stability period may be greater than 6 months.

  On the other hand, for aqueous emulsion compositions, this decomposition temperature can be lowered in some cases to room temperature. It is then generally desirable to condition the emulsion in at least two packages for storage. In this case, the "pot life" of the composition is substantially improved over that of the compositions comprising a known tin catalyst. This "pot life" duration is, for example, three times greater than that observed on a composition without a solvent comprising a

  equimolar amount of dibutyltin diacetylacetonate.

  By effective amount of latent catalyst is generally meant according to the invention, a content of 0.001 to 6 parts, preferably 0.01 to 3 parts (calculated by weight of tin metal), latent catalyst of formula (1) for 100 parts by weight of dry extracts from the sum of

polymers (A) and (B).

  The coating compositions according to the invention do not generally comprise mineral fillers. However, the presence of fillers, preferably siliceous (precipitated silica, fumed silica, diatomaceous earth, crushed quartz, etc.), generally used in silicone elastomer compositions, is not excluded in the content of I

- 11 -

  at 50 parts of filler per 100 parts of polymer (A) in particular for

  make thin coatings from a few gm to several mm thick.

  Polymers (A) and (B) have been known for a long time.

  The polymers (A) can be chosen from polydimethylsiloxane bones with hydroxyl end groups (with silanol ends), with a viscosity of at least 10 mPa.s at 25 ° C. These polymers (A) comprise low-viscosity oils ranging, for example, from 10 mPa.s at 5,000 mPa.s, viscous oils 5,000 to 10 mPa.s and viscosity gums

greater than 106 mPa.s.

  The polymers (B) can be linear, cyclic or branched.

  The viscosity of the polymers (B) ranges from 2 mPa.s at 25 ° C. to

000 mPa.s at 25 C.

  In the case where the composition is used without a solvent, the viscosity of the polymers (A) and (B) is chosen such that the viscosity of the mixture, that is to say of the composition is between

  and 5000 mPa.s, preferably between 100 and 3000 mPa.s at 25 C.

  The compositions according to the invention may be emulsified, dispersed or diluted in water or put in solution in a volatile organic solvent compatible with the composition, chosen, for example, from alkanes, petroleum fractions containing paraffinic compounds, toluene, toluene. heptane, xylene, isopropanol, methyl isobutyl ketone, tetrahydrofuran, chlorobenzene, chloroform, 1,1,1-trichloroethane, monoethylene glycol and methylene glycol derivatives. Preferably, the water or the solvent forms at the time of use of

  99% by weight of the dispersion or solution.

  During the crosslinking treatment involving the evaporation of the water or the solvent, the composition cures and is therefore useful as a coating composition for flexible supports made of metal, paper,

  plastic material, cardboard, etc .....

  The compositions according to the invention can also be used as compositions for rendering a non-adherent material, such as metal foils, glass, plastics or paper, to

  other materials to which it would normally adhere.

3S

- 12 -

  In the examples, all products analyzed by NMR are diluted in deuterated benzene unless otherwise indicated. Travel

are given in ppm.

EXAMPLE 1

  Preparation and decomposition of 2-acetoxyethyl dibutyltin chloride: a) - Preparation: a stoichiometric solution of chlorodibutyltin hydride and vinyl acetate in anhydrous cyclohexane is exposed under nitrogen for 1 hour at UV, at 30 C. At the end of the reaction

  The solvent is removed under vacuum at room temperature.

  Spectral characteristics: RMM H (pure) 6: 4.2 (2H, t), 1.7 (3Hs); 1.6 - 0.9 (20H, m); J (Alsnl)! = 81 Hz ;: (l9snAH) = 85 NMR 119Sn 8: 74.6 b) Decomposition: After 1 hour 15 minutes at 90 ° C,

  product is decomposed into chlorodibutyltin acetate.

  Spectral characteristics: H 6 NMR: 2.0 - 0.8 (m) Sn NMR 6: -28 (broad)

EXAMPLE 2

  Preparation and decomposition of lauroyloxy-2-ethyl-dibutyltin chloride: a) - Preparation: the procedure of Example 1 is repeated except that the exposure lasts 2 hours and the vinyl acetate is replaced

by vinyl laurate.

- 13 -

  Spectral characteristics: H (pure) NMR: 4.15 (2H, t) 2.2 - 0.9 (43H, m);

3 117 1 3 119 1

  | (Sn H) = 81 Hz and 5j (Sn H) I = 85 Hz b) - Decomposition: after 2 hours at 90 ° C., the product is

  completely decomposed into chlorodibutyltin laurate.

  Spectral characteristics: H 6 NMR: 2.2 (2Ht); 1.7 - 0.8 (39Hm) 11Sn NMR 6: -29 (broad)

EXAMPLE 3

  Preparation and decomposition of 2-ethoxyethyl dibutyltin chloride: a) - Preparation: the procedure of Example 1 is repeated except that the exposure lasts 3 hours at 5 ° C. and the vinyl acetate is

  replaced by vinyl ether and ethyl.

  Spectral characteristics: H-NMR 6: 3.5 - 2.9 (4H, m) 1.8 - 0.8 (23H, m) | J (SnH) | = 66Hz NMR 9Sn 6: 103.6 b) - Decomposition: after 1 hour 20 minutes at 150 ° C, the

  product is completely decomposed into ethoxychlorodibutyltin.

  Spectral characteristics: H-NMR 6: 3.9 (2H, q); 1.8 - 0.9 (21H, m) NMR 119 Sn 6: -113.0

- 14 -

EXAMPLE 4

  Preparation and decomposition of 2-acetoxyethyl dibutyltin acetate: a) - Preparation: to a solution of 2-acetoxyethyl dibutyltin chloride in anhydrous toluene is added a large excess of silver acetate. The medium is stirred for 15 minutes at room temperature, then

  filtered. The solvent is then removed under vacuum.

  Spectral characteristics: H (pure) NMR 6: 4.4 (2H, m); 2.0 (3Hs); 1.95 (3H, s); 1.6 - 0.9 (20H, m) I J (SnH)! = 77 Hz b) - Decomposition: after 1 hour at 75 ° C, the product is

  completely decomposed to dibutyltin diacetate.

  Spectral characteristics: H-NMR 6: 2.0 (6H, s); 1.65 - 0.9 (18H, m) NMR Sn 6: -156.3 -1 IR (CO): 1605, 1570, 1425 cm (F)

EXAMPLE 5

  Preparation and decomposition of lauroyloxy-2-ethyl-dibutyltin laurate: a) - Preparation: the same procedure as in Example 4 is repeated except that the starting chloride is lauroyloxy-2-chloride

  ethyl dibutyltin. The exchange is carried out using potassium laurate.

  Spectral characteristics: 1H NMR 6: 4.4 (2H, m), 2.0 - 0.9 (66H, m); NMR Sn O: 35.9

- 15 -

  b) - Decomposition: after 2 hours at 75 C, the product has

  totally gone to lead to dibutyltin dilaurate.

  Spectral characteristics: 1H NMR: 2.2 (4Ht); 1.6 - 0.9 (60H, m)

RN119 S

RMM Sn 6: -152.5

EXAMPLE 6

  Preparation and decomposition of acetylacetonate of 2-acetoxyethyl dibutyltin: a) - Preparation: the procedure of Example 4 is repeated

  except that the exchange is carried out with potassium acetylacetonate.

  Spectral characteristics: 1H 6 H NMR: 5.3 (1H, s); 4.4 (2H, m); 2.0 (3Hs); 1.8 (6H, s); 1.7 - 0.9 (20H, m) 13J (117SnH1) = 68 Hz NMR 19Sn 6: 38.8 b) Decomposition: after 1 hour at 120 ° C., the product is decomposed completely into a mixture of dibutyltin diacetylacetonate , from

  diacetate dibutyltin and acetylacetonate dibutyltin acetate.

  Spectral characteristics: 9Sn 6 NMR: -260 (broad); -155 (dibutyltin diacetate)

  -400 (very broad, dibutyltin diacetylacetonate).

- 16 -

EXAMPLE 7

  Preparation and decomposition of 2-Lauroyloxyethyl-dibutyltin acetylacetonate: a) - Preparation: the procedure of Example 5 is repeated

  except that the exchange is carried out with potassium acetylacetonate.

  Spectral characteristics: H-NMR: 5.35 (1Hs); 4.4 (2Hm); 2.20 (2H, t); 1.85 (6Hs); 1.5 - 0.9 (41 Hm) NMR Sn 6: 39.6 b) - Decomposition: after 3 hours at 120 ° C., the product has completely disappeared to give a mixture of the same type as that obtained

in example 6.

  Spectral characteristics: Sn NMR 6: -263 (broad); -151.4 (dibutyltin dilaurate)

  -400 (very broad, dibutyltin diacetylacetonate).

EXAMPLE 8

  Preparation and decomposition of 2-acetoxyethyl dibutyltin hydride: a) - Preparation: a solution of 11.6 mmol of vinyl acetate, 6.3 g (26.8 mmol) of dibutyltin dihydride and 1, 8 g of anhydrous cyclohexane, placed under nitrogen in a pyrex tank thermostated at 20 C, is exposed to UV for two hours. Excess stannic dihydride and the solvent are removed under high vacuum (10 KPa) at room temperature. Product analyzes show that hydride (1)

  is obtained in admixture with 20 to 30% Bu2Sn (CH2CH2OCOCH3) 2.

- 17 -

  Spectral characteristics: H (pure) NMR 6: 5.0 (1H, m); 4.3 (2H: m); 1.8 (3Hs); 1.5 - 0.9 (20Hm); | J (SnH)! = 38 Hz NMR 119Sn 6: -100.0 IR (film): v (SnH) = 1840 cm-1 (F) b) - Decomposition: after 3 hours at 110 ° C, the hydride is

  completely decomposed into active catalyst.

EXAMPLE 9

  Preparation and decomposition of 2-Lauroyloxyethyl dibutyltin hydride: a) - Preparation: the procedure of Example 8 is repeated

  except that vinyl acetate is replaced by vinyl laurate.

  Spectral characteristics: H (pure) NMR 6: 5.0 (1H, m); 4.4 (2H, m); 2, 3 (2H, t); 1.6 - 0.9 (41H, m); 13J (SnH) I = 39 Hz; NMR 119 Sn 6: -99.50 b) Decomposition: after 4 hours at 110 ° C., the hydride is

  completely decomposed into active catalyst.

EXAMPLE 10

  Use of latent catalyst for the preparation of polyurethanes: Preparation of a reaction mass: by mixing a diol,

  of a diisocyanate and an organotin compound.

- 18 -

  Reagents: the diol used is a mixture of 1,4-butanediol and a molecular weight polyether of which each end of chain has an OH function; the diisocyanate used is IPDI: isocyanato methyl-3-trimethyl-3, 5.5 cyclohexylisocyanate of formula:

H-N = C = 0

CH -N = C = 0

  the organotin compound is used in a proportion of 0.03 part of compound per 100 parts by weight (of solids) of the diol and of the IPDI. Procedure: in a vacuum flask is introduced: - 5.26 g of polyether, - 0.8 g of butanediol-1,4 The mixture is degassed and 1 ml of a solution is introduced into

  0.63 mmol of organotin compound in 25 ml of anhydrous ether.

  The solvent is evaporated under vacuum and 3.94 g of IPDI are added.

  The final reaction mixture is degassed in 2 minutes.

  Two reaction mixtures are carried out: one with the latent catalyst 2-lauroyloxy ethyl dibutyltin acetylacetonate designated C1, the other with a known catalyst, called C2 dibutyltin diacetylacetonate. A third mixture is produced without a catalyst. Each mixture is divided into two lots. On a first batch, the gel time ("pot life" duration) at room temperature (27 C) is measured and the second one measures the time required for

gel taken at 140 C.

  The results are summarized in Table 1 below.

- 19 -

TABLE i

  I "Sn" WITHOUT CATALYST CATALYST Cl CATALYST C2 Duration of "pot life" at 27 OC 6 hours 2 hours 40 minutes Gel time at 140 C 21 minutes 5 minutes 4 minutes 30 s Table 1 shows that the duration "pot life" at room temperature of the mixture containing the latent catalyst is three times longer than that of the mixture containing the catalyst. At 140 ° C., the latent catalyst regains all its activity very rapidly since it does not take longer for this preparation to gel than for that

containing the catalyst.

- 20 -

EXAMPLE 11

  Use of a latent catalyst for the crosslinking of organopolysiloxane composition: The following mixture is homogenized in ambient air: 23 g of β-dihydroxypolydimethylsiloxane oil, with a viscosity of 1000 mPa.st -1 g of a polyhydromethylsiloxane oil having trimethylsilyl termini, with a viscosity of 20 mPa.s, SiH / SiOH molar ratio = 9,

  0.178 millimole of organotin compound.

  A first mixture comprises, as organotin compound of

  2-Lauroyloxyethyl ethyl dibutyltin acetylacetonate, designated C1.

  A second mixture comprises as organotin compound

  dibutyltin diacetylacetonate, referred to as C2.

  Each of these two mixtures is divided into two lots.

  In the first two batches, the stability of the mixtures with ambient air is determined by measuring the time required for each of the mixtures to reach 150,000 mPa.s at 29 C. A CARRIMED rheometer is used for this purpose, on which a cone system is fitted. / thermostat plate

at 29 OC.

  On the second two batches, the crosslinking time is measured

   C for a composition having a thickness of 10 mm.

  The results obtained are collated in Table 2 below.

- 21 -

TABLE 2

CATALYST C1 CATALYST C2

  Duration of "pot life" at 29 C 2 hours 30 minutes

_ _ _ _ _ _ _ _ _ _

  Crosslinking time at 150 ° C. 10 minutes 10 minutes From table 2, it can be seen that the duration of "pot life" in the ambient air is with C1 nearly 3 times longer than with C2, for a time of

crosslinking at 150 C analog.

- 22 -

Claims (5)

  1. - Tetracoordinated or pentacoordinated tin compounds (IV) of the general formula: R Y   In which: the radicals R, which may be identical or different, are chosen from a linear or branched C1-C20 alkyl radical; and ## STR2 ## a mononuclear aryl, arylalkyl and alkylaryl radical, the alkyl part of which is C1-C6, 1 2   the radicals R and R, which are identical or different, are chosen from a hydrogen atom, a cyano radical, a C1-C6 alkyl radical, an alkoxycarbonyl radical whose alkyl part is C1-C6, and R and R can together form a saturated hydrocarbon ring having from 5 to 8 carbon atoms, the radical R is chosen from a hydrogen atom, a linear or branched C 1 -C 20 alkyl radical, a linear or branched C 1 -C 20 alkoxy radical, a mononuclear aryl radical and a mononuclear aryloxy radical, - a is 0 or 1.   the radical Y is chosen from a hydrogen atom, a halogen atom, a linear or branched C 1 -C 20 alkoxy radical, a linear or branched C 1 -C 20 acyloxy radical and a chelate group of formula: - 23 - O- C- R4 / \ C R5 (2) 6 Q _ C -R   In which: the radicals R 1 and R 2, which may be identical or different, are chosen from a radical R and a C 1 -C 5 alkoxy radical; the radical R is chosen from a hydrogen atom, an R 4 radical or else R form with R a divalent cyclic hydrocarbon radical in C5-C12.   2 - Tin compounds (IV) according to claim 1, characterized in that - R is chosen from butyl, octyl and 2-ethylhexyl radicals and the two radicals R are identical, - R is H, - R2 is H, - a = 1, - R is chosen from methyl, ethyl and undecyl radicals,   Y is H. Cl, acetyloxy, lauroyloxy and acetylacetonate.   3. - Tin compounds (IV) according to claim 1, chosen from: 2-acetyloxyethyl dibutyltin chloride: R = butyl, R = R = Hs R = methyl, Y = Cl1 a = 1, - chloride of 2-Lauroyloxyethyl dibutyltin: R = butyl, R = R = H, R = undecyl, Y = Cl, a = 1, 2-ethoxy-ethyl-dibutyltin chloride: R = butyl, R1 = R = H. R = ethyl, Y = C1, a = O, 2-acetyloxy ethyl dibutyltin acetate: R = butyl, R = R = H, R = methyl, Y = acetoxyl, a = 1, lauroyloxy-2-ethyl ethyl dibutyltin laurate: R = butyl, R = R = HE R = undecyl, Y = lauroyloxyl, a = 1, - 24 -   2-acetyloxy-ethyl-dibutyltin acetylacetonate: R 2 = butyl, R = R = H, R = methyl, Y = acetylacetonate (penten-2-one-4-oxy-2), a = 1, lauroyloxy acetylacetonate 2 ethyl dibutyltin: i 2 3 os R = butyl, R = R = H, R = undecyl, Y = acetyl acetonate (2-penten-2-one oxy-2), a = 1.   2-acetyloxyethyl dibutyltin hydride 1 2 3   R = butyl, R = = Y, R =, methyl, a = 1 - 2-Lauroyloxyethyl dibutyltin hydride: R 2 = R 2 butyl = R = Y = HR = undecyl and a = 1, 4. Process of thermal decomposition of a compound such as   defined in any one of claims 1 to 3, characterized in that   heating said compounds to obtain the product of formula: R2 Sn-Y O (C) R he has o   in which R, R, Y and a have the same meaning as in formula (1).   6. - Process according to claim 4, characterized in that an effective amount of a nucleophilic agent chosen from water, a secondary organic amine, an organic alcohol, an organosilicon compound, is added.   silanol function and an organic mercapto functional compound (SH).   6. - Use of a compound as defined in any one   Claims 1 to 3 as a catalyst for the preparation of polyurethane   by reacting an organic polyisocyanate with an organic compound containing at least two active hydrogen groups and initiating the catalysis of the reaction by heating the reaction mixture to a   temperature at least equal to the decomposition temperature of said compound. - 25 -   7. - Use of a compound as defined in any one   of claims 1 to 3 as a crosslinking catalyst of a mixture of a   silanol-terminated polydiorganosiloxane A and a polyorganohydrogensiloxane B, by carrying said mixture comprising an effective amount of said compound at a temperature equal to or greater than the thermal decomposition of said compound with optional evaporation of the   solvent or water present in the mixture.